The present invention relates to one or more portable structures of the type used to provide shelter for people and/or equipment. The shelters may be formed at least partially of flexible material, for example, fabric. The present invention is especially well-adapted for use in remote and rugged locations where it is difficult and/or time-consuming to configure one or more shelters for particular end uses, and in situations where flexibility of use, convenience, durability, and/or ease of set-up and storage are desirable. However, the present invention provides important advantages over the prior art in other conditions and situations as well.